1. Field of the Invention
This invention relates to lighting fixtures and more particularly to in-grade lighting fixtures.
2. Description of the Related Art
Conventional in-ground or in-grade lighting fixtures are typically buried all or partially below ground level and include a light emitter that illuminates up from below ground level. They can be buried in the earth or covered by hardscape such as concrete, asphalt, wood, pavers, tile, etc. The fixtures are typically used to illuminate walls, columns, flags, trees, signs or a pathway.
One type of in-grade lighting fixture generally comprises a housing and lens made of glass or other rigid and transparent material that is attached to an opening in the top of a housing. The housing contains various components including the light emitter that is arranged to emit light through the lens and electrical components that are used to power and operate the light emitter. When the light fixture is installed in-grade, the housing is typically below ground level and the lens is left uncovered so light can shine up through it. The electrical components can include a power supply, power converters, transformers, and mounting hardware for the light emitter. To hold all of these components, the housing can extend relatively deep into the ground (i.e. 14 to 16 inches).
During installation of these types of light fixtures, a hole is typically dug for the housing, the housing is placed in the hole and the hole is back filled around the housing. Any hardscape is then installed around the lens, leaving the lens uncovered.
In-grade light fixtures can have an optical chamber that contains the light emitter (lamp), with the optical chamber arranged in the housing so that light from the lamp emits through an upper housing opening. One disadvantage of conventional optical chambers is that condensation can develop inside the chamber through the heating and cooling of the lamp. These types of fixtures also have ballasts that contain electronic components such as transformers and capacitors. These ballasts can also develop condensation during heating and cooling that can cause failure or reduced life of the components.
The most common problems resulting from water inside the housing include corrosion, electrical shorts, shortened life of the ballast (power converter) or transformer and shortened lamp life. In addition, water entry into the electrically sensitive areas can create risk of electrocution for those working on the housing.
In other conventional light fixtures one or more enclosures can be included inside the housing to hold electrical components, which can increase the overall size of the light fixture. Conventional light fixtures also do not provide flexibility in the placement of enclosures to allow the light fixture to be configured to meet space constraints during installation.